Is this blight?

[sweet-pea]

I'm not sure if this will work, but I was wondering whether this is blight or something else?  I have 2 rows of this variety (can't remember which it is) and all the other plants seem health but this one seems very ill  :(

http://www.flickr.com/photos/71479785@N00/211695454/

http://www.flickr.com/photos/71479785@N00/211695453/

sweet-pea

[sweet-pea]

[saddad]

Only looked at the first as the comp. froze on me. Doesn't look like it.. just dieing back... a fine white mould around the edges of the damage on underside of leaves is the acid test...
???

[sweet-pea]

Thanks Saddad, that's put my mind at rest.  I keep assuming that it's just die back, but then there is always that niggle at the back of my mind that it could be blight.